The 49ers’ Delanie Walker grabs a pass at the Broncos’ 1-yard line on a ball that is just out of the reach of Broncos defensive backs Brian Dawkins (20) and Champ Bailey. The play set up the 49ers for a tying touchdown early in the fourth quarter.

LONDON — It was the type of play for the 49ers that never should have worked.

On their side, there was the former third-string quarterback, who was making his first start in three years, chucking a deep pass — while throwing off his back foot. The ball was intended for a backup tight end, who hadn’t caught a pass in the past three games and only seven passes all season.

On the other side, for the Broncos, were two likely Hall of Fame defensive backs in deep coverage.

So who do you like? Troy Smith and Delanie Walker for the 49ers, or the Broncos’ Brian Dawkins and Champ Bailey?

In the 49ers’ 24-16 victory against the Broncos on Sunday at Wembley Stadium, it was the duo you would least expect that helped start the Broncos’ defensive undoing.

The Broncos were leading 10-3 early in the fourth quarter when Smith took off scrambling to his right, chased by Broncos defensive linemen Ryan McBean and Ronald Fields. Smith, the former Heisman Trophy winner who was anointed as the 49ers’ new starter on Wednesday, heaved the ball deep just as he approached the Broncos’ sideline, and it was Walker who landed with the ball at the 1-yard line, not Dawkins, who was in coverage, or Bailey, who was helping.

“(Smith) just threw it up, and Dawkins was standing in front of the guy he was throwing it to, and last second, Dawkins got a little nudge. I’m holding back because I think (Dawkins) is going to get it or tip it,” Bailey said. “I didn’t want us both to jump and the ball come down to him if one of us tipped it. And the ball happened to come down right in (Walker’s) hands.

“Just the luck of the draw sometimes.”

Dawkins immediately pleaded to an official for a flag for offensive pass interference, arguing that Walker got away with a push. After the game, however, Dawkins said he wouldn’t dispute the noncall.

“I’ve never been someone in my career that’s ever made excuses. I just have to make that play. Regardless of the circumstances, I have to make that play,” Dawkins said.

Two plays later, Smith scored on a 1-yard run, rolling to his right on a bootleg, then untouched into the end zone to tie the game at 10.

It was the type of confidence boost the ailing 49ers’ offense needed — and a deflating blow to the Broncos’ defense which to that point had shown improvement from last week’s debacle in Denver.

The 49ers went on to score touchdowns on each of their next two possessions. The Broncos’ next two drives went like this: penalty, three- and-out, punt; and Kyle Orton scramble and fumble.

Smith threw for 110 of his 196 yards in that fourth quarter. He consistently was able to escape the Broncos’ pass rush and was not sacked in the game.

The Broncos have given up fourth- quarter leads three times: at Jacksonville, vs. the Jets and now against San Francisco.

“Defensively, when we get a lead, we’ve got to win. And we’re not playing well enough right now, both sides of the ball, all three phases,” Bailey said. “We’ve got to clean it up. It’s just unprofessional.”

WASHINGTON — Thirty games into the 82-game NHL season, and nearly six weeks after the Matt Duchene trade, Avalanche general manager Joe Sakic discussed the state of his team before Tuesday’s 5-2 loss at the Washington Capitals.